Fuel injector with increased feed area

ABSTRACT

Provided is a nozzle tip assembly having at least one tube member housed within a tubular shell, the tube member having a first passage connecting the first outlet port to the first inlet port and a second passage connecting the second outlet port to the second inlet port. The configuration of the tube member allows the tubular shell to be sized such that separation of fluid flowing around the tubular shell is reduced, thereby reducing the amount of aerodynamic wake that occurs in an injector.

RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/495,424 filed Jun. 10, 2011, which is hereby incorporated herein byreference.

FIELD OF INVENTION

The present invention relates generally to fuel injectors, and moreparticularly to fuel injectors for gas turbine engines.

BACKGROUND

A gas turbine engine typically includes one or more fuel injectors fordirecting fuel from a manifold to a combustion chamber of a combustor.Each fuel injector typically has an inlet fitting connected eitherdirectly or via tubing to the manifold, a tubular extension or stemconnected at one end to the fitting, and one or more spray nozzlesconnected to the other end of the stem for directing the fuel into thecombustion chamber. A fuel passage (e.g., a tube or cylindrical passage)extends through the stem to supply the fuel from the inlet fitting tothe nozzle. Appropriate valves and/or flow dividers can be provided todirect and control the flow of fuel through the nozzle and/or fuelpassage.

SUMMARY OF INVENTION

The present invention provides a nozzle tip assembly having at least onetube member housed within a tubular shell, the tube member having afirst passage connecting the first outlet port to the first inlet portand a second passage connecting the second outlet port to the secondinlet port. The configuration of the tube member allows the tubularshell to be sized such that separation of fluid flowing around thetubular shell is reduced, thereby reducing the amount of aerodynamicwake that occurs in an injector.

According to one aspect of the invention, a nozzle tip assembly for afluid injector includes a supply connector having first and secondsupply passages and first and second outlet ports to which the first andsecond supply passages are respectively connected, a nozzle assemblyhaving first and second nozzle flow passages extending respectively fromfirst and second inlet ports to respective nozzle outlets and a feed armhaving an outer tubular shell connecting the nozzle assembly to thesupply connector, and at least one tube member housed within the tubularshell and spaced apart from the shell, the at least one tube memberhaving a first passage connecting the first outlet port to the firstinlet port and a second passage connecting the second outlet port to thesecond inlet port.

In an embodiment, the at least one tube member includes first and secondtubes adjacent to one another, the first tube connecting the firstoutlet port to the first inlet port and the second tube connecting thesecond outlet port to the second inlet port.

In another embodiment, the first and second tubes are parallel to oneanother.

In yet another embodiment, the first and second tubes each have firstand second end portions and an intermediate portion extending betweenthe first and second end portions, each of the end portions having awall thickness greater than a wall thickness of the respectiveintermediate portion.

In still another embodiment, each end portion has a radially outwardlyopening groove for receiving connecting material to couple the first andsecond tubes to the supply connector and nozzle assembly.

In a further embodiment, the feed arm has an oblong cross-section withrounded upstream and downstream ends.

In another embodiment, the assembly includes an adaptor interposedbetween the nozzle assembly and a housing of the injector, the adaptorhaving an annular wall and an opening extending through the annularwall, wherein the feed arm extends through the opening.

In yet another embodiment, the nozzle assembly has an upstream end and adownstream end, and wherein the upstream end of the nozzle assembly iscurved.

In still another embodiment, the upstream end of the nozzle assembly hasa curvature transitioning to a reverse curvature on the feed arm.

In a further embodiment, a fluid injector includes a housing in whichthe nozzle tip assembly according to claim 1 is assembled.

According to another aspect of the invention, a nozzle tip assembly fora fluid injector is provided including a nozzle assembly having at leastone nozzle flow passage extending from an inlet port to a nozzle outletand a feed arm having an outer tubular shell connecting the nozzleassembly to an adaptor, and at least one tube member housed within thetubular shell and spaced apart from the shell, the at least one tubemember including first and second end portions, an intermediate portionextending between the first and second end portions, and at least onepassage fluidly connecting the nozzle flow passage to a fluid deliverydevice, wherein each end portion has a wall thickness greater than awall thickness of the intermediate portion.

In an embodiment, each end portion has a radially outwardly openinggroove for receiving connecting material to couple the first end portionto a supply connector and the second end portion to the nozzle assembly.

According to another aspect of the invention, a nozzle assembly for afluid injector is provided including a body having an upstream end and adownstream end and a length extending from the upstream end to thedownstream end, a feed arm extending from the body, the feed arm havingan exterior surface and a width perpendicular to the length of the body,and at least one radially outwardly projecting fin extending from thebody downstream of the feed arm, wherein an upstream end of the fin isspaced along the length of the body from a downstream end of theexterior surface of the feed arm a distance that is at least four tenthsa width of the feed arm.

In an embodiment, the distance is at least forty-four hundredths thewidth of the feed arm.

The foregoing and other features of the invention are hereinafterdescribed in greater detail with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a portion of an exemplary gasturbine engine illustrating a fuel injector in communication with acombustor;

FIG. 2 is a fragmentary cross-sectional view of a fuel injector showingdetails of an exemplary nozzle tip assembly;

FIG. 3 is a partial fragmentary cross-sectional view of a fuel injectorshowing details of an exemplary nozzle tip assembly in accordance withthe invention;

FIG. 4 is a rear cross-sectional view of a nozzle assembly in accordancewith the invention;

FIG. 5 is a top view of a feed arm of the nozzle assembly;

FIG. 6 is a partial fragmentary cross-sectional view of another fuelinjector showing details of another exemplary nozzle tip assembly inaccordance with the invention;

FIG. 7 is a rear cross-sectional view of the nozzle assembly of FIG. 6;and

FIG. 8 is a top view of a feed arm of the nozzle assembly of FIG. 6.

DETAILED DESCRIPTION

Referring now in detail to the drawings and initially to FIG. 1, a gasturbine engine for a gas turbine is illustrated generally at 10. The gasturbine engine 10 includes an outer casing 12 extending forwardly of anair diffuser 14. The casing 12 and diffuser 14 enclose a combustor,indicated generally at 20, for containment of burning fuel. Thecombustor 20 includes a liner 22 and a combustor dome, indicatedgenerally at 24. An igniter, indicated generally at 25, is mounted tothe casing 12 and extends inwardly into the combustor 20 for ignitingfuel. The above components can be conventional in the art and theirmanufacture and fabrication are well known.

A fuel injector, indicated generally at 30, is received within anaperture 32 formed in the engine casing 12 and extends inwardly throughan aperture 34 in the combustor liner 22. The fuel injector 30 includesa fitting 36 exterior of the engine casing 12 for receiving fuel, as byconnection to a fuel manifold or line; a fuel nozzle tip assembly,indicated generally at 40, disposed within the combustor 20 fordispensing fuel; and a housing 42 interconnecting and structurallysupporting the nozzle tip assembly 40 with respect to fitting 36. Thefuel injector 30 is suitably secured to the engine casing 12, as bymeans of an annular flange 41 that may be formed in one piece with thehousing 42 proximate the fitting 36. The flange 41 extends radiallyoutward from the housing 42 and includes appropriate means, such asapertures, to allow the flange 41 to be easily and securely connectedto, and disconnected from, the casing 12 of the engine using, forexample, bolts or rivets.

The fuel injector 30 shown in FIG. 1 is of the type disclosed in U.S.patent application Ser. No. 11/625,539 and is exemplary of a fuelinjector to which principles of the invention may be applied. The nozzletip assembly may be replaced by a nozzle tip assembly according to thepresent invention, and an exemplary nozzle tip assembly is shown in FIG.2. For ease of description, the same reference numerals will be used todenote corresponding components.

As best seen in FIG. 2 when viewed in conjunction with FIG. 1, thehousing 42 includes a central, longitudinally-extending bore 50extending the length of the housing 42. A fuel conduit 52 extendsthrough the bore 50 and fluidly interconnects fitting 36 and an annularfuel delivery device 54 disposed in the housing 42. The fuel conduit 52has at least two internal passages for the passage of fuel.Alternatively, multiple fuel conduits may be provided with an internalpassage for the passage of fuel. The fuel conduit 52 is surrounded bythe bore 50 of the housing 42, and an annular insulating gap 56 isprovided between the external surface of the fuel conduit 52 and thewalls of the bore 50. The insulating gap 56 provides thermal protectionfor the fuel in the fuel conduit 52. The housing 42 has a thicknesssufficient to support nozzle tip assembly 40 in the combustor 20 whenthe injector 30 is mounted to the engine, and is formed of materialappropriate for the particular application.

The nozzle tip assembly 40 is configured for insertion into the fuelinjector 30, and in the illustrated embodiment, at a downstream end ofthe housing 42. The nozzle tip assembly 40 includes a nozzle adaptor 68that is coupled to the housing 42 at an upstream end of the housing 42by any suitable means, such as by brazing or welding at 72, oralternatively, the adaptor 68 may be integrally formed with the housing42. The nozzle tip assembly 40 also includes a fluid flow assembly 60that includes a nozzle assembly 62 and an air swirler 64. The nozzleassembly 62 is configured to receive fluid, such as fuel, from theannular fuel delivery device 54 in any suitable manner, such as by asupply connector 66. The nozzle assembly 62 may also be configured todisperse the fuel to the air swirler 64 to be mixed with air flowingthrough the fuel injector 30, and the fuel flow from the nozzle assembly62 can be metered based on the engine fuel manifold pressure.

The nozzle tip assembly 40 also includes a nozzle shroud 58 that may beinserted into the fuel injector 30 from the downstream end of thehousing 42, and may be coupled to the housing 42 at the downstream endby any suitable means, such as by welding at 70. Upon insertion into thefuel injector 30, the nozzle shroud 58 will at least be partiallysurrounded by the adaptor 68, and the nozzle assembly 62 will besupported interiorly of the nozzle shroud 58. A rearward portion of thenozzle assembly 62 may be coextensive with a rearward portion of thenozzle shroud 58 and the nozzle shroud 58 may radially outwardlysurround the nozzle assembly 62. A retention device, such as theretention device described in U.S. patent application Ser. No.12/612,977 which is hereby incorporated herein by reference, may used toprovide a secondary retention feature for holding the nozzle shroud 58to the adaptor 68 if the primary retention means, e.g. weld at 70, wasto fail during use of the nozzle tip assembly.

Turning now to FIG. 3, the fluid flow assembly 60, supply connecter 66and adaptor 68 are described in detail. The supply connector 66 has oneend coupled to the annular fuel delivery device 54, either directly orindirectly, and another end coupled to the nozzle assembly by anysuitable means. The supply connector has first and second supplypassages 80 and 82 and first and second outlet ports 84 and 86 to whichthe first and second supply passages 80 and 82 are respectivelyconnected. The supply connecter receives fluid in each supply passage80, 82 from the delivery device 54, and delivers the fluid to a tubemember coupled to the outlet ports 84 and 86 as described below.Although the supply connector is described as having two supplypassages, it will be appreciated that the supply connector 66 may havemore than two supply passages.

The nozzle assembly 62 includes a body 88 and a feed arm 90, which maybe integrally formed with the body. Disposed interiorly of the body arefirst and second nozzle flow passages 92 and 94 extending respectivelyfrom first and second inlet ports 96 and 98 to respective nozzle outlets100 and 102. The flow passages 92 and 94 may be substantiallyconcentric, for example with the second flow passage 94 surrounding thefirst flow passage 92. It will be appreciated that the nozzle assemblycan be of any duel feed type having an inlet for a first fluid and aninlet for a second fluid.

The feed arm 90 has an outer tubular shell 104 that connects the nozzleassembly 62 to the supply connector 66, for example by welding orbrazing the feed arm to the supply connector. Housed within the feed arm90 and spaced apart from the tubular shell 104 is at least one tubemember, and in the illustrated embodiment a first tube 110 and a secondtube 112, having a first passage 114 connecting the first outlet port 84of the supply connector 66 to the first inlet port 96 of the nozzleassembly 62 and a second passage 116 connecting the second outlet port86 to the second inlet port 98. The first and second tubes 110 and 112are adjacent to one another. For example the first and second tubes 110and 112 are parallel to one another. The first and second tubes 110 and112 may also be axially spaced from one another to provide a gap betweenthe tubes along with a gap between the tubes and the tubular shell 104.It will be appreciated that although the first tube 110 is illustratedas having a smaller diameter than the second tube 112, the diameters ofthe tubes may be any suitable diameter.

Each tube 110, 112 has a first end portion 118, 120; a second endportion 122, 124; and an intermediate portion 126, 128 extending betweenthe first and second end portions. The first and second end portions 118and 122 of the first tube 110 have a wall thickness greater than a wallthickness of the intermediate portion 126, and the first and second endportions 120 and 124 of the second tube 112 have a wall thicknessgreater than a wall thickness of the intermediate portion 128. The endportions 118, 120, 122 and 124 each have a radially outwardly openinggroove 130, 132, 134, 136, respectively, for receiving connectingmaterial to couple the first and second tubes 110 and 112 to the supplyconnector 66 and nozzle assembly 62. For example, the connectingmaterial may be a brazing compound in the form of a ring, such as anopen-ended ring 138, which is inserted into the groove. Alternatively,the end portions may be thicker than the intermediate portions toprovide a thickened portion to which a weld can be made. The thickenedend portions transition to the intermediate portion, for example by acurve, thereby reducing stress on the end portions.

Referring again to the nozzle assembly 62, the body 88 has an upstreamend 140 that is curved in any suitable manner, for example in a bulletnose shape, and the upstream end has a curvature transitioning to areverse curvature on the feed arm to reduce fluid separation of fluidflowing past the upstream end. By providing the first and second tubes110 and 112 adjacent to one another as shown in FIG. 3, the feed arm canbe formed having an oblong cross-section where the length from theupstream end to the downstream end is greater than a width of the feedarm. The feed arm can also be formed with rounded upstream anddownstream ends. The curvature and oblong shape of the feed arm 90reduces separation of fluid, such as air, flowing past the upstream end140 and the feed arm 90.

The nozzle tip assembly 60 also includes a plurality of radiallyoutwardly projecting fins 142 downstream of the feed arm 90. The fins142 are spaced from the downstream end of the feed arm along a length lof the body a distance d which in one embodiment is at least four tenthsa width w of the feed arm (0.4×w). In another embodiment, the distance dis at least forty-four hundredths the width w of the feed arm (0.44×w).In still another embodiment, the distance d is at least forty-eighthundredths the width w of the feed arm (0.48×w). In yet anotherembodiment, the distance d is at least one half the width w of the feedarm (0.5×w). During takeoff of an aircraft, for example, the oblong feedarm 90 allows for reduced separation of fluid flowing around the feedarm, and when used in combination with fins 142 spaced a distance x fromthe feed arm, the fluid on one side of the feed arm rejoins the fluid onthe other side of the feed arm prior to flowing past the fins 142,thereby reducing the amount of aerodynamic wake that occurs.

Referring again to the adaptor 68, which is coupled to the upstream endof the housing 42 as described above, the adaptor is interposed betweenthe nozzle assembly 62 and the housing 42. The adaptor 68 includes anannular wall 150 having an opening 152 extending therethrough. Theadaptor 68 also includes a recessed groove 154, recessed from an outerwall of the adaptor, surrounding the opening 152. When assembled, thefeed arm 90 extends through the opening 152 and is coupled to theadaptor by a connecting material positioned in the recessed groove 154.For example, the connecting material may be a brazing compound in theform of a ring, such as an open-ended ring 156, which is inserted intothe groove 154. After brazing, the braze material will fill the grooveand be substantially in-line with the outer wall of the adaptor.Additionally or alternatively, the adaptor may be formed with a recessedgroove that is recessed from an inner wall of the adaptor to receive aconnecting material to couple the adaptor to the feed arm.

Turning now to FIGS. 4 and 5, the feed arm 90 is shown having a circulartop portion 160 having a diameter substantially equal to a diameter ofthe supply connector 66. Alternatively, the supply connector 66 isunitary with the feed arm 90. The circular top portion 160 of the feedarm 90 is configured to be received in the opening 152 in the adaptor 68and to be coupled to the adaptor as described above. The circular topportion 160 has a wall thickness greater than a wall thickness of oblongtubular shell 104, and the thickened circular top portion transitions tothe tubular shell, for example by a curve. As noted above, the tubes 110and 112 are spaced from one another and from the tubular shell 104 toprovide s gap between the tubes and gaps between the tubes and theshell.

Turning now to FIG. 6-8, an exemplary embodiment of the injector isshown at 230. The injector 230 is substantially the same as theabove-referenced injector 30, and consequently the same referencenumerals but indexed by 200 are used to denote structures correspondingto similar structures in the injectors. In addition, the foregoingdescription of the injector 30 is equally applicable to the injector 230except as noted below. Moreover, it will be appreciated upon reading andunderstanding the specification that aspects of the injectors may besubstituted for one another or used in conjunction with one anotherwhere applicable.

Referring now to FIG. 6, the supply connector is formed as a singlecomponent with a tube member housed within the feed arm 290 and spacedapart from the tubular shell 304, which will herein be referred to assupply tube 308. The supply tube 308 has a first passage 314 connectingthe fuel delivery device to a first inlet port 296 of the nozzleassembly and a second passage 316 connecting the fuel delivery device toa second inlet port 298 of the nozzle assembly. The supply tube 308 isspaced from the tubular shell 304 to provide a gap between the supplytube and the shell. Although the first passage 314 is illustrated havinga smaller diameter than the second passage 316, it will be appreciatedthat the diameters of the passages may be any suitable diameter.

The supply tube 308 has an end portion 322 coupled to the nozzleassembly in any suitable manner. For example, the end portion 322 mayinclude a radially outwardly opening groove 335 for receiving aconnecting material 337 to couple the supply tube 308 to the nozzleassembly. The end portion may also include an extending portion 370 forsealing the first passage that extends past an end of the supply tube.The portion 370 has a groove or notch 372 for receiving a connectingmaterial 374 to couple the supply tube 308 to the inlet port 296 toprevent cross-leakage between the first and second passages.

Referring to FIGS. 7 and 8, the feed arm 290 is shown having a circulartop portion 360 provided to be received in the opening 352 in theadaptor 268 and to be coupled thereto. The circular top portion 360 hasa wall thickness greater than a wall thickness of oblong tubular shell304, and the thickened circular top portion transitions to the tubularshell, for example by a curve. As noted above, the tubular member 308 isspaced from the tubular shell 304 to provide an annular gap between thesupply tube and the shell.

Although the invention has been shown and described with respect to acertain embodiment or embodiments, it is obvious that equivalentalterations and modifications will occur to others skilled in the artupon the reading and understanding of this specification and the annexeddrawings. In particular regard to the various functions performed by theabove described elements (components, assemblies, devices, compositions,etc.), the terms (including a reference to a “means”) used to describesuch elements are intended to correspond, unless otherwise indicated, toany element which performs the specified function of the describedelement (i.e., that is functionally equivalent), even though notstructurally equivalent to the disclosed structure which performs thefunction in the herein illustrated exemplary embodiment or embodimentsof the invention. In addition, while a particular feature of theinvention may have been described above with respect to only one or moreof several illustrated embodiments, such feature may be combined withone or more other features of the other embodiments, as may be desiredand advantageous for any given or particular application.

What is claimed is:
 1. A nozzle tip assembly for a fluid injector,comprising: a supply connector having first and second supply passagesand first and second outlet ports to which the first and second supplypassages are respectively connected; a nozzle assembly having first andsecond nozzle flow passages extending respectively from first and secondinlet ports to respective nozzle outlets and a feed arm having an outertubular shell connecting the nozzle assembly to the supply connector;and at least one tube member housed within the tubular shell and spacedapart from the shell, the at least one tube member having a firstpassage connecting the first outlet port to the first inlet port and asecond passage connecting the second outlet port to the second inletport.
 2. The nozzle tip assembly according to claim 1, wherein the atleast one tube member includes first and second tubes adjacent to oneanother, the first tube connecting the first outlet port to the firstinlet port and the second tube connecting the second outlet port to thesecond inlet port.
 3. The nozzle tip assembly according to claim 2,wherein the first and second tubes are axially spaced apart from oneanother.
 4. The nozzle tip assembly according to claim 2, wherein thefirst and second tubes are parallel to one another.
 5. The nozzle tipassembly according to claim 2, wherein the first and second tubes eachhave first and second end portions and an intermediate portion extendingbetween the first and second end portions, each of the end portionshaving a wall thickness greater than a wall thickness of the respectiveintermediate portion.
 6. The nozzle tip assembly according to claim 5,wherein each end portion has a radially outwardly opening groove forreceiving connecting material to couple the first and second tubes tothe supply connector and nozzle assembly.
 7. The nozzle tip assemblyaccording to claim 6, wherein the connecting material is a brazingcompound.
 8. The nozzle tip assembly according to claim 1, wherein thefeed arm has an oblong cross-section with rounded upstream anddownstream ends.
 9. The nozzle tip assembly according to claim 8,wherein the feed arm has a length from the upstream end to thedownstream end that is greater than a width of the feed arm.
 10. Thenozzle tip assembly according to claim 1, wherein the supply connectoris unitary with the feed arm.
 11. The nozzle tip assembly according toclaim 1, further comprising an adaptor interposed between the nozzleassembly and a housing of the injector, the adaptor having an annularwall and an opening extending through the annular wall, wherein the feedarm extends through the opening.
 12. The nozzle tip assembly accordingto claim 11, wherein the adaptor has a recessed groove surrounding theopening for receiving connecting material to couple the adaptor to thefeed arm.
 13. The nozzle tip assembly according to claim 1, wherein thenozzle assembly has an upstream end and a downstream end, and whereinthe upstream end of the nozzle assembly is curved.
 14. The nozzle tipassembly according to claim 13, wherein the upstream end of the nozzleassembly has a curvature transitioning to a reverse curvature on thefeed arm.
 15. The nozzle tip assembly according to claim 1, furthercomprising an air swirler at least partially surrounding the nozzleassembly, wherein the nozzle assembly is configured to disperse fluidreceived from the at least one tube member to the air swirler to bemixed with air flowing through the injector.
 16. A fluid injectorincluding a housing in which the nozzle tip assembly according to claim1 is assembled.
 17. A nozzle tip assembly for a fluid injector,comprising: a nozzle assembly having at least one nozzle flow passageextending from an inlet port to a nozzle outlet and a feed arm having anouter tubular shell connecting the nozzle assembly to an adaptor; and atleast one tube member housed within the tubular shell and spaced apartfrom the shell, the at least one tube member including first and secondend portions, an intermediate portion extending between the first andsecond end portions, and at least one passage fluidly connecting thenozzle flow passage to a fluid delivery device; wherein each end portionhas a wall thickness greater than a wall thickness of the intermediateportion.
 18. The nozzle tip assembly according to claim 17, wherein eachend portion has a radially outwardly opening groove for receivingconnecting material to couple the first end portion to a supplyconnector and the second end portion to the nozzle assembly.
 19. Anozzle assembly for a fluid injector, comprising: a body having anupstream end and a downstream end and a length extending from theupstream end to the downstream end; a feed arm extending from the body,the feed arm having an exterior surface and a width perpendicular to thelength of the body; and at least one radially outwardly projecting finextending from the body downstream of the feed arm; wherein an upstreamend of the fin is spaced along the length of the body from a downstreamend of the exterior surface of the feed arm a distance d that is atleast four tenths a width of the feed arm.
 20. The nozzle assemblyaccording to claim 19, wherein the distance d is at least forty-fourhundredths the width of the feed arm.